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Background/Purpose: Adipose tissue contains progenitor cells that contribute to beneficial tissue expansion when needed by de novo adipocyte formation (classical white or beige fat cells with thermogenic potential). However, in chronic obesity, they can exhibit an activated pro-fibrotic, extracellular matrix (ECM)-depositing phenotype that highly aggravates obesity-related adipose tissue dysfunction. Methods: Given that progenitors' fibrotic activation and fat cell browning appear to be antagonistic cell fates, we have examined the anti-fibrotic potential of pro-browning agents in an obesogenic condition. Results: In obese mice fed a high fat diet, thermoneutral housing, which induces brown fat cell dormancy, increases the expression of ECM gene programs compared to conventionally raised animals, indicating aggravation of obesity-related tissue fibrosis at thermoneutrality. In a model of primary cultured murine adipose progenitors, we found that exposure to β-hydroxybutyrate selectively reduced Tgfβ-dependent profibrotic responses of ECM genes like Ctgf, Loxl2 and Fn1. This effect is observed in both subcutaneous and visceral-derived adipose progenitors, as well as in 3T3-L1 fibroblasts. In 30 patients with obesity eligible for bariatric surgery, those with higher circulating β-hydroxybutyrate levels have lower subcutaneous adipose tissue fibrotic scores. Mechanistically, β-hydroxybutyrate limits Tgfβ-dependent collagen accumulation and reduces Smad2-3 protein expression and phosphorylation in visceral progenitors. Moreover, β-hydroxybutyrate induces the expression of the ZFP36 gene, encoding a post-transcriptional regulator that promotes the degradation of mRNA by binding to AU-rich sites within 3′UTRs. Importantly, complete ZFP36 deficiency in a mouse embryonic fibroblast line from null mice, or siRNA knock-down in primary progenitors, indicate that ZFP36 is required for β-hydroxybutyrate anti-fibrotic effects. Conclusion: These data unravel the potential of β-hydroxybutyrate to limit adipose tissue matrix deposition, a finding that might exploited in an obesogenic context.

Overhauser dynamic nuclear polarization (ODNP) NMR of solutions at high fields is usually mediated by scalar couplings that polarize the nuclei of heavier, electron-rich atoms. This leaves 1 H-detected NMR outside the realm of such studies. This study presents experiments that deliver 1 H-detected NMR experiments on relatively large liquid volumes (60 ∼ 100 μL) and at high fields (14.1 T), while relying on ODNP enhancements. To this end 13 C NMR polarizations were first enhanced by relying on a mechanism that utilizes e - - 13 C scalar coupling interactions; the nuclear spin alignment thus achieved was then passed on to neighboring 1 H for observation, by a reverse INEPT scheme relying on one-bond J CH -couplings. Such 13 C → 1 H polarization transfer ported the 13 C ODNP gains into the 1 H, permitting detection at higher frequencies and with higher potential sensitivities. For a model solution of labeled 13 CHCl 3 comixed with a nitroxide-based TEMPO derivative as polarizing agent, an ODNP enhancement factor of ca. 5x could thus be imparted to the 1 H signal. When applied to bigger organic molecules like 2- 13 C-phenylacetylene and 13 C 8 -indole, ODNP enhancements in the 1.2-3x range were obtained. Thus, although handicapped by the lower γ of the 13 C, enhancements could be imparted on the 1 H thermal acquisitions in all cases. We also find that conventional 1 H- 13 C nuclear Overhauser enhancements (NOEs) are largely absent in these solutions due to the presence of co-dissolved radicals, adding negligible gains and playing negligible roles on the scalar e - → 13 C ODNP transfer. Potential rationalizations of these effects as well as extensions of these experiments, are briefly discussed., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Homonuclear isotropic mixing modules allow J-coupled spins to exchange magnetization even when separated by chemical shift offsets that exceed their couplings. This is exploited in TOtal Correlation SpectroscopY (TOCSY) experiments and its variants, which facilitate these homonuclear polarization exchanges by applying broadband RF pulses. These then establish an effective Hamiltonian in which chemical shift offsets are erased, while J-coupling terms -including flip-flop components- remain active. The polarization that these non-secular terms will transfer among systems of chemically inequivalent sites over the course of a mixing period, are widely used modules in 1D and in multidimensional liquid-state NMR. Homonuclear correlation experiments are also common in solids NMR, particularly among X =  13 C or 15 N nuclei. Solids NMR experiments are often challenged by high-power RF demands which have led to a family of homonuclear solid-state correlation experiments that avoid pulsing on the nuclei of interest, and focus instead on the 1 Hs that are bonded to them. These solid experiments usually reintroduce/strengthen 1 H-X dipolar couplings; these, in conjunction with assistance from rotational resonance effects, bring back the truncated X-X dipolar interactions and facilitate the generation of cross peaks. The present study explores whether a similar goal can be achieved for solution-state counterparts, based on the reintroduction of truncated flip-flop terms in the J-coupling Hamiltonian via the pulsing on other, heteronuclear species. A proposal to achieve this is derived, and the resulting HOmonucleaR Recoupling by hEteroNuclear DecOUplingS (HORRENDOUS) approach to provide correlations between like nuclei without pulsing on them, is demonstrated., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Modern people spend most of their time indoors. Therefore, controlling indoor air quality is one of the most important factors for health. The indoor fine dust concentration is affected by the outdoor fine dust concentration. When the latter is high, it increases due to immersion. Therefore, improving the sealing performance of a building is an effective strategy to reduce indoor fine dust concentration during periods of severe outdoor fine dust without considering indoor fine dust generating factors. Traditional methods of improving the airtightness of a building have focused on replacing windows or doors. However, for reasons such as constructability and economic feasibility, more diverse technologies need to be considered. Due to this necessity, this study applied technologies such as sealing film, sealing lid, and padding to the educational building, and then derived the airtight performance through the blower door experiment, and measured the fine dust concentration to evaluate the effect. As a result of the experiment, it was analyzed that air leakage was reduced by up to 37% and fine dust by 22%., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Here, we describe a method for obtaining a dynamic nuclear polarization (DNP)-enhanced double-quantum filtered (DQF) two-dimensional (2D) dipolar 13 C- 13 C correlation spectra of bone-tissue material at natural 13 C abundance. DNP-enhanced DQF 2D dipolar 13 C- 13 C spectra were obtained using a few different mixing times of the dipolar-assisted rotational resonance (DARR) scheme and these spectra were compared to a conventional 2D through-space double-quantum (DQ)-single-quantum (SQ) correlation spectrum. While this scheme can only be used for an assignment purpose to reveal the carbon-carbon connectivity within a residue, the DQF 13 C- 13 C dipolar correlation scheme introduced here can be used to obtain longer distance carbon-carbon constraints. A DQF pulse block is placed before the DARR mixing scheme for removing dominant 13 C single-quantum (SQ) signals because these SQ 13 C signals are overwhelmingly large compared to those 13 C- 13 C dipolar cross-peaks generated and therefore saturate the dynamic range of the NMR detection. This approach exhibits strong enough 2D cross-peaks in a dipolar 13 C- 13 C correlation spectrum and potentially provides pairwise 13 C- 13 C dipolar constraints because the dipolar truncation effect as well as multi-step signal propagations involving a spin cluster that contains more than two spins can be ignored probabilistically. To obtain fast signal averaging, AsymPolPOK was used to provide a short 1 H DNP signal build-up time (1.3 s) and to expedite our MAS DNP NMR acquisitions while still maintaining a satisfactory DNP enhancement factor (ε = 50). Under long DARR mixing, a t 1 -noise-like artifact was observed at a site that possesses a large chemical shift anisotropy (CSA) and a few different strategies to address this problem were discussed., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Particles of fine dust are pollutants that adversely affect indoor air quality and exacerbate human respiratory diseases. The aging of the building was pointed out as a source of fine dust indoors. The aging of buildings has various causes of deterioration. During various deterioration, friction adversely affects the building floor finish. In this study, an accelerated friction deterioration device was used to confirm the generation of fine dust particles through the frictional deterioration of floor finishes in buildings. The study found that the concentration of fine dust particles attributed to deteriorating flooring was 327 mg/m 3 in PM2.5 and 4828 mg/m 3 in PM10 and confirmed that particle distribution differs depending on the surface of the flooring. Particles of 10 µm or less were observed through particle analysis. The study confirmed that fine dust particles did not diffuse in a specific direction and that the detected fine dust particles could be attributed to deterioration. Further research is needed on the detection of fine dust in degraded building finishing materials., (Copyright © 2021 Elsevier B.V. All rights reserved.)

In order to vitalize the use of wood, which is a sustainable resource, increase the utilization of resources through the recycling of wood waste, and reduce environmental pollution in the waste disposal process, biocomposite was manufactured by using biochar which can be produced with wood waste and is effective in carbon isolation. The thermal characteristics and acetaldehyde adsorption performance of the prepared biocomposite were evaluated based on the pore characteristics, surface functional groups, crystal structure, and elemental analysis results of the biochar. As a result of the experiment, as the content of biochar increased, the thermal conductivity of the biocomposite decreased and the specific heat was not affected. The acetaldehyde concentration tended to decrease as the content of biochar increased, adsorbed up to 4.4685 ppm of acetaldehyde more than the reference. From these results, it is judged that the biocomposite produced in this study can function as a sustainable composite that uses waste wood to improve indoor air quality and satisfies the performance as a building material., (Copyright © 2021 Elsevier Inc. All rights reserved.)

To obtain high thermal performance composite phase change materials (PCMs), various other supporting materials have been utilized to encapsulate organic PCMs. In this study, four carbon materials (biochar, activated carbon, carbon nanotubes, and expanded graphite) were introduced to support heptadecane. The composite PCMs were designed using vacuum impregnation techniques. The structural stability, chemical compatibility, thermal stability, and thermal energy storage capacity of the as-prepared materials were systematically characterized using differential scanning calorimetry, Fourier-transform infrared spectroscopy, etc. Among the supporting materials, expanded graphite had a high PCM content of 94.5%, whereas it was low for biochar-supported PCM (25.7%). Meanwhile, the latent heat storage capacity ranged from 53.3 J/g to 195.9 J/g. It was observed that the intermolecular interactions between the PCM and supporting materials and the surface functionality of the encapsulating agents play a leading role in the thermal performance of the composite PCMs. Furthermore, pore structures such as specific surface area, total pore volume, and pore size distribution have a combined effect on the crystallinity of heptadecane in the composite PCMs. The study will provide insight into developing and designing carbon-based composite PCMs for heat-storage purposes., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Wood is a sustainable resource and building material. It provides an excellent response to climate change and has excellent insulation performance. However, structural defects may occur due to decay from moisture, resulting in poor dimensional stability. The rich organic substances contained in wood can lead to mold when the moisture content is consistently high, adversely affecting the health of occupants. Therefore, we attempted to compensate for the disadvantages of wood in regard to water stability while maintaining the high thermal insulation performance and carbon dioxide storage capacity, using biochar from thermally decomposed spruce under oxygen limiting conditions. A wood-derived biocomposite was prepared by mixing biochar and soft wood-based chips using the hot-press method, and the thermal conductivity, specific heat, water vapor resistance factor, moisture adsorption, and moisture desorption performances were analyzed. The thermal conductivity of WB10 with 10 wt% biochar content was 0.09301 W/mK. This is a 7.98% decrease from 0.10108 W/mK, the thermal conductivity of WB0 without biochar. The water vapor resistance factor tended to increase when the biochar ratio increased. As the proportion of biochar increased, the equilibrium moisture content in high relative humidity tended to decrease, and it was found that the moisture adsorption and desorption performances were affected by the ratio of the biochar. Therefore, wood-derived biocomposites using biochar can be used in environmentally friendly materials, with improved thermal insulation performance and water stability., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Thermal insulation material, an essential building material, is used to preserve heat or block heat gains in buildings. Insulation material is currently attracting significant attention, and thermal conductivity, i.e., thermal insulation performance, is expressed at a very low value. Therefore, since the era of industrialization, several chemicals have been used to secure thermal insulation performance in each sector; therefore, the resulting hazards have increased. To date, researches have been mainly conducted to secure the low thermal conductivity of insulating material; however, the hazards remain unaddressed. Therefore, this study quantitatively evaluates 18 building construction products and the emission of pollutants and harmful gas during combustion events. Pollutant emission was conducted using the 20-L small chamber method according to the ISO 16000, and formaldehyde, total volatile organic compounds, and five volatile organic compounds were analyzed. Gas hazard evaluation during combustion was evaluated by KS F 2271: Fire Retardant Testing Method of Interior Finishes and Structures as the average behavioral stop time of rats under thermal insulation combustion conditions., (Copyright © 2020 Elsevier B.V. All rights reserved.)

As buildings generally have become larger and more airtight, the ventilation rate has decreased further, causing insufficient ventilation which leads to moisture problems such as condensation, mold growth, reduction of thermal insulation performance and corrosion of building materials. In order to prevent moisture problems, it is essential to understand the thermal and hygric status of a climatic region. In this study, the hygrothermal environmental zone considering not only the thermal environment but also the hygric environment was derived by analyzing the climate environment in Korea. The hygrothermal environmental zone has the advantage of being able to take into account the hygrothermal environment of the unexplored regions and to cope with climate change by quantifying the thermal and hygric environmental indexes in each region. Finally, the long-term moisture risk of the building envelopes was evaluated. As the results, it is considered that the proposed hygrothermal environmental zone is appropriate and it is necessary to consider the hygric environment in order to secure the moisture stability of the building envelope., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Aerogel is a superinsulating material with an extremely low thermal conductivity (<0.015 W/m·K), high porosity (>99 %), and extremely low density. In this study, a new closed-cell spray polyurethane (PU) foam with aerogel was developed and investigated. In particular, a PU foam with aerogel and graphite (PUAG) was prepared by mixing aerogel for reducing the thermal conductivity of the foam and a small concentration of graphite for improving its flame-retardancy performance. The performance of the prepared PUAG was analyzed via several tests, including density measurements, thermal-conductivity measurements, morphology examination, flame-retardancy evaluation, thermogravimetric analysis, and dynamic heat transfer analysis. A 20 % reduction in the thermal conductivity compared with traditional PU was observed. Additionally, the PUAG exhibited a reduction in the total smoke production and a 10 % reduction in the surface peak temperature., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Building materials have been developed mainly for thermal performance, strength, low energy consumption, and aesthetics. Consequently, large amounts of chemicals have been added to building products, resulting in the release of abundant pollutants that adversely affect human health. In particular, pollutants from the materials used to build modern dwellings can cause sick house syndrome, which leads to health resilience problems and diseases. In this study, more than 100 investigations were conducted annually from 2004 to 2017 by using the 20 L small chamber method to analyze the contents of formaldehyde (HCHO) and total volatile organic compounds (TVOC) released from 2780 building products in total. High emissions were released by some building components with raw materials containing hazardous chemicals. However, since the 2004 enactment of a legal standard for the regulation of emissions of harmful substances in building products, the pollutant emissions have tended to decrease over the years. As a result of the experiment, all 2780 building materials met the legal standard on average. Therefore, legal restrictions on the release of hazardous materials from building products have achieved reductions in pollutant emissions., Competing Interests: Declaration of Competing Interest There is no competing interests., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The thermal performance of hybrid hollow plaster panels (HHPPs) was analyzed using the amount of phase change material (PCM) injection as a variable according to the size of the hollow area. This study focuses on n-octadecane, an organic PCM that is used for storing latent heat during the phase change range and to improve thermal transmittance using exfoliated graphite nanoplatelets (xGnPs), which have a high thermal conductivity. When xGnP is applied to n-octadecane, the thermal conductivity improves by 225%, and it is confirmed that the thermal storage or release of the phase change material is an active reaction. The thermo-physical properties of the xGnP and n-octadecane composites were analyzed using a thermal conductivity analyzer (TCi) and differential scanning calorimetry (DSC). The thermal stability of PCM was analyzed over a long duration of 10,000 thermal cycles. The thermal performance of the PCM/plaster composite panel using the dynamic heat transfer device was determined. The peak temperature through the HHPP significantly reduced by 3.8 ℃ in an internal room, and the time-lag effect was confirmed to be 1.56 h. The results indicate that up to 36.6 J/m 2 of thermal energy was stored in the 26-Px/O, corresponding to approximately 247% of the available thermal energy of the reference panel., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Biochar and red clay were used to develop eco-friendly building materials with improved thermal and mechanical performance. Rice husk, coconut shell, and bamboo were prepared by thermally decomposing as biochar. Thermal conductivity measurements, scanning electron microscopy imaging, compressive strength measurements, and an infrared heat transfer experiment were performed, and the results showed that the mixture of biochar tends to lower the thermal conductivity. The compressive strength of specimens mixed with rice husk decreased, but that of specimens mixed with coconut shell and bamboo tended to increase. The infrared heat transfer test showed that the thermal performance of the mixed rice husk specimens was significant, while the specimen mixed with coconut shell and bamboo showed thermal performance improvement. A comprehensive evaluation of the improvement in thermal performance and strength indicated that a 10 wt.% mixture of bamboo was the most effective. Therefore, it was possible to effectively determine the type and weight ratio of biochar to red clay binder an important step in the study of biochar and red clay building materials., (Copyright © 2019 Elsevier B.V. All rights reserved.)

In the present study, the synthesis of an organic group-modified alumina by the sol-gel method is proposed. This material has shown to have an enhanced catalytic performance with grafted organic groups and showed an improved stability. The prepared material has shown to have several O - H groups and an enhanced surface acidity. The alumina acidity was improved by incorporating thiol groups by grafting method, which promotes the tautomerization of fructose to its furanose form. Furthermore, the grafting of sulfonic groups catalyzes its dehydration. The modified alumina was thermally treated up to 200 °C to improve the functional groups stability. After, this modified material was packed into a continuous reactor system, designed and built by this group, to obtain 5-hydroxymethylfurfural (5-HMF) from fructose dissolved in a single-phase solution of tetrahydrofuran (THF) and H 2 O (4:1 w/w). The catalytic activity of this material was evaluated by the reaction of fructose dehydration at different reaction temperatures (60, 70, 80 and 90 °C). Fructose conversion and selectivity toward 5-HMF were determined by high performance liquid chromatography (HPLC), obtaining 95% and 73% respectively for the highest temperature. The catalyst showed an efficient stability after 24 hours in continuous flow at 70 °C. The loss of sulfur content was 15%, but the fructose conversion yield and the selectivity to 5-HMF after 24 hours of continuous reaction did not undergo significant changes (less than 5%). The nuclear magnetic resonance (NMR) tests confirmed the presence of the thiol and sulfonic groups before and after 24 hours of reaction, as well as the conservation of the same structure, demonstrating the efficient catalytic performance of the material. The catalysts were characterized by nitrogen adsorption/desorption, X-ray diffraction and infrared (IR) spectroscopy. Also, before and after use by utilizing elemental analysis and   1 H - 13 C cross-polarization magic-angle spinning (CPMAS) and dynamic-nuclear polarization (DNP)-enhanced   1 H - 13 C and   1 H - 29 Si CPMAS as well as directly excited   29 Si magic-angle spinning (MAS) NMR methods in solid-state.

One approach to enhance the energy efficiency of buildings is the integration of construction materials of latent heat storage biocomposites, which are prepared by vacuum impregnating the phase change material into biochar. Biochar is used because it is highly utilized and environmentally-friendly, and the selected phase change materials are fatty acid type which are bio-based material and have a low risk of depletion. Experimental results showed that latent heat storage biocomposite possesses excellent exudation and thermal stability as characterized by 0.1727 W/mK of thermal conductivity comparable to that for a gypsum board, and good chemical compatibility as its amount of latent heat tends to decrease as compared with that of pure phase change material. Results of the numerical analysis showed further that latent heat storage biocomposite efficiently reduced the maximum energy consumption of reference building models by 531.31 kWh per year. Thus, both results validate the claim that latent heat storage biocomposite is a promising building material., (Copyright © 2019 Elsevier Inc. All rights reserved.)

We explore the use of cross-polarization magic-angle spinning (CPMAS) methods incorporating an adiabatic frequency sweep in a standard Hartman-Hahn CPMAS pulse scheme, to achieve signal enhancements in solid-state NMR spectra of rare spins under fast MAS spinning rates, including spin-1/2, integer spin, and half-integer spin nuclides. These experiments, dubbed Broadband Adiabatic INversion Cross-Polarization Magic-Angle Spinning (BRAIN-CPMAS) experiments, involve an adiabatic inversion pulse on the S-channel of a rare spin nuclide while simultaneously applying a conventional spin-locking pulse on the I-channel ( 1 H). The signal enhancement imparted by this CP scheme on the S-spin is broadbanded, while employing low RF field strengths on both I- and S-channels. A feature demanded by these BRAIN-CPMAS methods is to impose a selective adiabatic frequency sweep over a single MAS spinning centerband or sideband, to avoid interference between the MAS modulation and sweeps over multiple sidebands. Upon implementing this swept-CP method, a number of MAS-driven processes happen, including broadband zero- and double-quantum CP transfers, and MAS-driven rotary-resonance phenomena. When this CP method is applied to integer and half-integer quadrupolar nuclei at very fast MAS spinning rates, a favorable double-quantum CP condition is found that can be easily achieved, and avoids the level-crossings among various m s energy levels that complicate quadrupolar CPMAS NMR experiments along lines first shown by Alex Vega. An additional CP mechanism was found in the 1 H- 2 H case, involving static-like zero-quantum CP modes driven by a quadrupole-modulated RF-dipolar zero-order recoupling under MAS. All these phenomena were examined using average Hamiltonian theory, numerical simulations, and experiments on model compounds. Sensitivity-enhanced, distortion-free CP over wide bandwidths were predicted and observed for S = 1/2 and for S = 1 ( 2 H) under fast MAS rates. BRAIN-CPMAS also delivered undistorted central transition NMR spectra of half-integer quadrupolar nuclei, while utilizing low RF field strengths that avoid complex level-crossing effects under high MAS rates., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Nuclear magnetic resonance (NMR) is an intrinsically insensitive technique, with Boltzmann distributions of nuclear spin states on the order of parts per million in conventional magnetic fields. To overcome this limitation, dynamic nuclear polarization (DNP) can be used to gain up to three orders of magnitude in signal enhancement, which can decrease experimental time by up to six orders of magnitude. In DNP experiments, nuclear spin polarization is enhanced by transferring the relatively larger electron polarization to NMR active nuclei via microwave irradiation. Here, we describe the design and performance of a quasi-optical system enabling the use of a single 395 GHz gyrotron microwave source to simultaneously perform DNP experiments on two different 14.1 T ( 1 H 600 MHz) NMR spectrometers: one configured for magic angle spinning (MAS) solid state NMR; the other configured for solution state NMR experiments. In particular, we describe how the high power microwave beam is split, transmitted, and manipulated between the two spectrometers. A 13 C enhancement of 128 is achieved via the cross effect for alanine, using the nitroxide biradical AMUPol, under MAS-DNP conditions at 110 K, while a 31 P enhancement of 160 is achieved via the Overhauser effect for triphenylphosphine using the monoradical BDPA under solution NMR conditions at room temperature. The latter result is the first demonstration of Overhauser DNP in the solution state at a field of 14.1 T ( 1 H 600 MHz). Moreover these results have been produced with large sample volumes (∼100 µL, i.e. 3 mm diameter NMR tubes)., (Copyright © 2018 Elsevier Inc. All rights reserved.)

The use of frequency-swept radiofrequency (rf) pulses for enhancing signals in the magic-angle spinning (MAS) spectra of half-integer quadrupolar nuclides was explored. The broadband adiabatic inversion cross-polarization magic-angle spinning (BRAIN-CPMAS) method, involving an adiabatic inversion pulse on the S-channel and a simultaneous rectangular spin-lock pulse on the I-channel ( 1 H), was applied to I(1/2)→S(3/2) systems. Optimal BRAIN-CPMAS matching conditions were found to involve low rf pulse strengths for both the I- and S-spin channels. At these low and easily attainable rf field strengths, level-crossing events among the energy levels |3/2〉,|1/2〉,|-1/2〉,|-3/2〉 that are known to complicate the CPMAS of quadrupolar nuclei, are mostly avoided. Zero- and double-quantum polarization transfer modes, akin to those we have observed for I(1/2)→S(1/2) polarization transfers, were evidenced by these analyses even in the presence of the quadrupolar interaction. 1 H- 23 Na and 1 H- 11 B BRAIN-CPMAS conditions were experimentally explored on model compounds by optimizing the width of the adiabatic sweep, as well as the rf pulse powers of the 1 H and 23 Na/ 11 B channels, for different MAS rates. The experimental data obtained on model compounds containing spin-3/2 nuclides, matched well predictions from numerical simulations and from an average Hamiltonian theory model. Extensions to half-integer spin nuclides with higher spins and potential applications of this BRAIN-CPMAS approach are discussed., (Copyright © 2017 Elsevier Inc. All rights reserved.)

A solid-state rotational-echo double resonance (REDOR) NMR method was introduced to identify the ϕ- and ψ-torsion angle from a (1)H-(15)N or (1)H-(13)C' spin system of alanine-like residues in a selectively, uniformly, or extensively (15)N-/(13)C-labeled peptide. When a C(α)(i) or a (15)N peak is site-specifically obtainable in the NMR spectrum of a uniformly (15)N/(13)C-labeled sample system, the ψ- or ϕ-torsion angle specified by the conformational structure of peptide geometry involving (15)N(i)-(1)H(α)i-(15)N(i+1) or (13)C'(i-1)-(1)H(N)i-(13)C'(i) spin system can be identified based on (13)C(α)- or (15)N-detected (1)H(α)-(15)N or (1)H(N)-(13)C REDOR experiment. This method will conveniently be utilized to identify major secondary motifs, such as α-helix, β-sheet, and β-turn, from a uniformly (15)N-/(13)C-labled peptide sample system. When tested on a (13)C-/(15)N-labeled model system of a three amino acid peptide Gly-[U-(13)C, (15)N]Ala-[U-(13)C, (15)N]Leu, the ψ-angle of alanine obtained experimentally, ψ = -40 ± 30°, agreed reasonably well with the X-ray determined angle, ψ = -39°., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Herein is described a useful approach in solid-state NMR, for selecting homonuclear (13)C-(13)C spin pairs in a multiple-(13)C homonuclear dipolar coupled spin system. This method builds upon the zero-quantum (ZQ) dipolar recoupling method introduced by Levitt and coworkers (Marin-Montesinos et al., 2006) by extending the originally introduced one-dimensional (1D) experiment into a two-dimensional (2D) method with selective irradiation scheme, while moving the (13)C-(13)C mixing scheme from the transverse to the longitudinal mode, together with a dramatic improvement in the proton decoupling efficiency. Selective spin-pair recoupling experiments incorporating Gaussian and cosine-modulated Gaussian pulses for inverting specific spins were performed, demonstrating the ability to detect informative, simplified/individualized, long-range (13)C-(13)C homonuclear dipolar coupling interactions more accurately by removing less informative, stronger, short-range (13)C-(13)C interactions from 2D correlation spectra. The capability of this new approach was demonstrated experimentally on uniformly (13)C-labeled Glutamine and a tripeptide sample, GAL., ((c) 2010 Elsevier Inc. All rights reserved.)